Automations with the Slack API in JavaScript/

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Get Channel Properties

Learn to use Slack API calls to get various data from channels and the workspace.

We'll cover the following...

Get message history
Get the channel info
Get the list of all channels
Get the list of members from a channel
Get the replies to a message

In this lesson, we retrieve information from Slack’s Conversations API. This set of endpoints is useful when we create an application for different workspaces.

Let’s look at the following endpoints in this lesson:

conversations.history: This endpoint fetches a channel’s history, including messages and events.
conversations.info: This endpoint retrieves information about a channel.
conversations.list: This endpoint lists all channels in a Slack team.
conversations.members: This endpoint retrieves members of a channel.
conversations.replies: This endpoint retrieves a thread of messages posted to a channel or chat.

Get message history

To acquire the message history, we access the https://slack.com/api/conversations.history endpoint. This endpoint allows us to get all the messages that have been sent in a channel. You’re advised to use the limit parameter so that the response is not too large.

Parameter	Type	Category	Description
`token`	token	required	Authentication tokens carry the required scopes that govern the usage of different Slack applications and APIs. We usually pass these tokens as an HTTP Authorization header or as a POST parameter.
`channel`	string	required	This parameter specifies the channel to which the message will be posted. It can be a public channel, a private group, or an IM channel (direct message). The value for this parameter can either be an encoded ID or a name of a channel.
`cursor`	string	optional	This parameter is a string of characters used to "point" to the next "page" of data. We paginate through collections of data by setting the `cursor` parameter to a `next_cursor` attribute returned by a previous request's `response_metadata`.
`inclusive`	boolean	optional	This parameter includes messages with the `latest` or `oldest` timestamp in the results. It is only used when one of the timestamps is specified. If a message has the same timestamp as `latest` or `oldest`, it will only be included in the response if the `inclusive` parameter is `true`.
`latest`	string	optional	This is the latest timestamp. All messages before this timestamp will be included in the results. Its default is the current time.
`limit`	number	optional	This is the maximum number of items to return. Items fewer than the requested number may be returned.
`oldest`	string	optional	This is the oldest timestamp. All messages after this timestamp will be included in the results.

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Javascript (babel-node)

import fetch from "node-fetch";
const url = new URL("https://slack.com/api/conversations.history");
const headerParameters = {
  Authorization: "Bearer {{TOKEN}}",
  "Content-Type": "application/json; charset=UTF-8",
};
const queryParameters = new URLSearchParams({
  channel: "{{CHANNEL_ID}}",
  limit: 2,
});
const options = {
  method: "GET",
  headers: headerParameters,
};
async function getHistory() {
  try {
    url.search = queryParameters;
    const response = await fetch(url, options);
    printResponse(response);
  } catch (error) {
    printError(error);
  }
}
getHistory();

Parameter	Type	Category	Description
`token`	token	required	Authentication tokens carry the required scopes that govern the usage of different Slack applications and APIs. We usually pass these tokens as an HTTP Authorization header or as a POST parameter.
`channel`	string	required	This parameter specifies the channel to which the message will be posted. It can be a public channel, a private group, or an IM channel (direct message). The value for this parameter can either be an encoded ID or a name of a channel.
`include_locale`	boolean	optional	Set this to `true` to receive the locale for this conversation. Defaults to `false`
`include_num_members`	boolean	optional	Set to `true` to include the member count for the specified conversation. Defaults to `false`

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Javascript (babel-node)

import fetch from "node-fetch";
const url = new URL("https://slack.com/api/conversations.info");
const headerParameters = {
  Authorization: "Bearer {{TOKEN}}",
  "Content-Type": "application/json; charset=UTF-8",
};
const queryParameters = new URLSearchParams({
  channel: "{{CHANNEL_ID}}",
});
const options = {
  method: "GET",
  headers: headerParameters,
};
async function getChannelInfo() {
  try {
    url.search = queryParameters;
    const response = await fetch(url, options);
    printResponse(response);
  } catch (error) {
    printError(error);
  }
}
getChannelInfo();

Parameter	Type	Category	Description
`token`	token	required	Authentication tokens carry the required scopes that govern the usage of different Slack applications and APIs. We usually pass these tokens as an HTTP Authorization header or as a POST parameter.
`cursor`	string	optional	This parameter is a string of characters used to "point" to the next "page" of data. We paginate through collections of data by setting the `cursor` parameter to a `next_cursor` attribute returned by a previous request's `response_metadata`.
`exclude_archived`	boolean	optional	We set this to `true` to exclude archived channels from the list.
`limit`	number	optional	This is the maximum number of items to return. Items fewer than the requested number may be returned.
`team_id`	string	optional	This is the encoded team ID to list channels in. It is required if the token belongs to an org-wide application.
`types`	string	optional	This parameter is used to mix and match channel types by providing a comma-separated list of any combination of `public_channel`, `private_channel`, `mpim`, `im`.

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Parameter	Type	Category	Description
`token`	token	required	Authentication tokens carry the required scopes that govern the usage of different Slack applications and APIs. We usually pass these tokens as an HTTP Authorization header or as a POST parameter.
`channel`	string	required	This parameter specifies the channel to which the message will be posted. It can be a public channel, a private group, or an IM channel (direct message). The value for this parameter can either be an encoded ID or a name of a channel.
`cursor`	string	optional	This parameter is a string of characters used to "point" to the next "page" of data. We paginate through collections of data by setting the `cursor` parameter to a `next_cursor` attribute returned by a previous request's `response_metadata`.
`limit`	number	optional	The maximum number of items to return. Items fewer than the requested number may be returned.

Press + to interact

Javascript (babel-node)

import fetch from "node-fetch";
const url = new URL("https://slack.com/api/conversations.members");
const headerParameters = {
  Authorization: "Bearer {{TOKEN}}",
  "Content-Type": "application/json; charset=UTF-8",
};
const queryParameters = new URLSearchParams({
  channel: "{{CHANNEL_ID}}",
});
const options = {
  method: "GET",
  headers: headerParameters,
};
async function getChannelMembers() {
  try {
    url.search = queryParameters;
    const response = await fetch(url, options);
    printResponse(response);
  } catch (error) {
    printError(error);
  }
}
getChannelMembers();

Parameter	Type	Category	Description
`token`	token	required	Authentication tokens carry the required scopes that govern the usage of different Slack applications and APIs. We usually pass these tokens as an HTTP Authorization header or as a POST parameter.
`channel`	string	required	This parameter specifies the channel to which the message will be posted. It can be a public channel, a private group, or an IM channel (direct message). The value for this parameter can either be an encoded ID or a name of a channel.
`ts`	string	required	This parameter specifies the timestamp of the message.
`cursor`	string	optional	This parameter is a string of characters used to "point" to the next "page" of data. We paginate through collections of data by setting the `cursor` parameter to a `next_cursor` attribute returned by a previous request's `response_metadata`.
`inclusive`	boolean	optional	This parameter includes messages with the `latest` or `oldest` timestamp in the results. It is only used when one of the timestamps is specified. If a message has the same timestamp as `latest` or `oldest`, it will only be included in the response if the `inclusive` parameter is `true`.
`latest`	string	optional	This is the latest timestamp. All messages before this timestamp will be included in the results. Its default is the current time.
`limit`	number	optional	The is the maximum number of items to return. Items fewer than the requested number may be returned.
`oldest`	string	optional	This is the oldest timestamp. All messages after this timestamp will be included in the results.

Press + to interact

Javascript (babel-node)

import fetch from "node-fetch";
const url = new URL("https://slack.com/api/conversations.replies");
const headerParameters = {
  Authorization: "Bearer {{TOKEN}}",
  "Content-Type": "application/json; charset=UTF-8",
};
const queryParameters = new URLSearchParams({
  channel: "{{CHANNEL_ID}}",
  ts: "{{TS}}",
});
const options = {
  method: "GET",
  headers: headerParameters,
};
async function getMessageReplies() {
  try {
    url.search = queryParameters;
    const response = await fetch(url, options);
    printResponse(response);
  } catch (error) {
    printError(error);
  }
}
getMessageReplies();

Ask

Introduction

Chat Using the Application

Conversations Using an App

File Management

Users

Manage Reactions

Slack's Bolt Framework

Conclusion

Appendix

Get Channel Properties

Get message history

Get the channel info

Get the list of all channels

Get the list of members from a channel

Get the replies to a message